1. Field of the Invention
The present invention generally relates to ordnance for destroying a target and, more particularly, is concerned with a projectile incorporating a unique penetrator capable of penetrating a successively more difficult multiple plate array in a target.
2. Description of the Prior Art
Armor-piercing projectiles having an outer shell and containing small amounts of igniting, incendiary and/or explosive charges are conventional weapons of warfare used in both offensive and defensive modes. Such projectiles are most effective when their destructive force is unleased after they impact and hopefully penetrate the target. Thus, it is common practice to incorporate some means for delaying ignition of the incendiary and/or explosive charges carried by the projectile until after impact. Representative of the prior art employing this practice are the projectiles disclosed in U.S. Patents to Giljarhus et al (U.S. Pat. No. 3,677,181), Strandli (U.S. Pat. Nos. 3,980,020; 3,980,021; and 3,922,996).
In addition, there was a Frankford Arsenal APIE (armor-piercing-incendiary-explosive) test round described at page 129 of Hackler, Woodin and Scranton, History of U.S. Military Small Arms Ammunition, Volume II, 1940-1945 (1978). This was one of literally dozens of test round labeled FAT1 which led to the M8 incendiary round. Little is now known about this round, except that it was one of many FAT1 rounds developed in World War II, but this particular versions was never produced in anything more than experimental quantities because another design was selected for the M8 round.
A common countermeasure used by designers of warfare array of multiple plates for the purpose of making it difficult, if not impossible, to penetrate and destroy the equipment. One technique adopted to bolster the penetrating power of the projectile is to employ primary and secondary penetration elements in the weapon. Representative of the prior art employing this technique are the projectiles disclosed in U.S. Patents to Weiss (U.S. Pat. No. 2,564,870) and Strandli et al (U.S. Pat. No. 4,353,302). In particular, the projectile of Weiss includes two shell elements, each containing an explosive charge and being disposed one behind the other in tandem-like fashion. The rear shell element is given an armour piercing power higher than that of the front shell element and the front element is designed to pierce only a relatively thin sheet and then explode behind it. Next, the rear element is designed to pierce an armour plate located beyond the thin sheet and explode behind the thicker plate. Thus, the Weiss projectile is intended to pass through walls of increasing resistance, defeating this particular countermeasure designed to protect the equipment.
While the aforementioned basic technique embodied by the Weiss projectile has merit, it is anticipated that the particular construction disclosed in the patent will achieve its objective, if at all, only under very limited conditions. First of all, the rear shell element interfits with the front shell element in such a way that much of the impact force of the front element against the target will be transmitted to the rear shell causing dissipation of much of its energy and penetrating power. Second, the explosion of the explosive in the front shell apparently acts rearwardly against the front of the rear shell, tending to slow it further, Therefore, the first wall of the target must be very fragile compared to and be only a short distance from the second armour plate in order for the rear element to still retain sufficient energy to pierce the plate and to pierce the second plate before the rear shell detonates. Thirdly, the Weiss construction fails to ensure that the charge contained in the rear shell element will always be used to its full capability for its effectiveness is totally dependent upon the rear element successfully piercing the armour plate. Should the rear element fail to penetrate the plate, the explosion of the charge will only destroy the rear element in front of the plate and presumably fail to destroy the equipment protected by the plate. Fourth, the Weiss projectile uses a rapid fire mechanical fuze which makes the delay too short for many applications. Fifth, the Weiss projectile has a fat rear shell which in order to penetrate must make a big hole which takes a lot of Kinetic energy. Sixth, Weiss teaches a rear shell which has a shoulder to support the front shell and this shoulder apparently impinges flatly against the target, thus using up extra energy.
Consequently, in view of the above-described shortcomings in the design of the Weiss projectile, and the unrealized nature of the FAT1 APIE round, a need still remains to come up with an improved projectile design which will more completely realize the potential of the technique underlying the Weiss design.